1. Field of the Invention
The present invention relates to a mounting circuit and a method for producing a semiconductor-chip-mounting circuit. In particular, the present invention relates to a mounting circuit and a method for producing a semiconductor-chip-mounting circuit obtained by solder-bonding of a connecting terminal of a mounting circuit to a bump of a semiconductor chip.
2. Description of the Related Art
In production processes of semiconductor chips, such as integrated circuits (ICs) and large scale integrations (LSIs: ICs having a degree of integration of 1,000 to 10,000), continuity tests are performed by connecting semiconductor chips to test jigs, such as probe cards, thereby reducing waste in which defective semiconductor chips are mounted on mounting circuits.
In probe cards used in performing continuity tests for ball grid array (BGA) semiconductor chips or land grid array (LGA) semiconductor chips, contacts (probes) that are each in the form of a conical helix are connected to surfaces of connecting terminals arranged at a narrow pitch of several tens of micrometers on each probe card in order to bring the contacts into contact with either many globular each having an external diameter of several tens of micrometers or many land bumps each having a width of several tens of micrometers and arranged at a narrow pitch of several tens of micrometers on each semiconductor chip.
When the contacts are pressed against the bumps, the elastic force of the contacts is applied to the bumps. As a result, the semiconductor chips are electrically connected to the probe cards. Thereby, continuity tests for semiconductor chips can be performed without the connection of semiconductor chips with probe cards (see Japanese Unexamined Patent Application Publication No. 2005-50598).
In the case where semiconductor chips are mounted on mounting circuits, desired semiconductor chip are produced, continuity tests are performed for the semiconductor chips before the semiconductor chips are mounted on the mounting circuits, and only the semiconductor chips passed the continuity tests are mounted on the mounting circuits. In other words, hitherto, a semiconductor-chip-mounting circuit obtained by mounting a semiconductor chip on a mounting circuit has been produced through a step of producing the semiconductor chip, an inspection step of the semiconductor chip, and a step of mounting the semiconductor chip.
Even in the case where after a continuity test is performed, a semiconductor chip is connected to a mounting circuit to produce a semiconductor-chip-mounting circuit, if the mounting circuit is defective, or if the connection is defective, defective continuity in the semiconductor-chip-mounting circuit is caused. The semiconductor chip bonded by soldering cannot be removed from the semiconductor-chip-mounting circuit. Thus, disadvantageously, the semiconductor-chip-mounting circuit having defective continuity cannot be reused and must be discarded.
In the early stage of the development of a semiconductor-chip-mounting circuit, the semiconductor chip has a design defect, in some cases. Therefore, even when the semiconductor chip is mounted on a mounting circuit to produce a semiconductor-chip-mounting circuit after the semiconductor chip and the mounting circuit are separately subjected to a continuity test, disadvantageously, defective continuity may occur in the stage of the production of the semiconductor-chip-mounting circuit.
When only a single semiconductor chip is mounted on a semiconductor-chip-mounting circuit, the probability of the occurrence of the defective continuity in the semiconductor-chip-mounting circuit is low, and production costs thereof are not very high. In the case of a large-density semiconductor-chip-mounting circuit including many semiconductor chips, however, the probability of the occurrence of the defective continuity in the semiconductor-chip-mounting circuit is increased as the number of semiconductor chips mounted is increased. Furthermore, production costs of the semiconductor-chip-mounting circuit is increased as the number of semiconductor chips mounted is increased. Thus, even if a small number of semiconductor-chip-mounting circuit is discarded, loss due to disposal may be large.
In recent years, mounting circuits on which semiconductor chips are mounted are not limited to common, inexpensive rigid circuit boards or flexible wiring circuit boards by development of mounting techniques such as chip on glass (COG), chip on chip (COC), and chip on parts (COP). That is, expensive circuits, such as transparent glass substrates used for liquid crystal displays (LCDs), semiconductor chips, and electronic components, may be used as mounting circuits. In particular, costs of the transparent glass substrates used for LCDs are increased as sizes of screens are increased. Thus, a state in which defective continuity occurs in the stage of the production of the liquid crystal displays (semiconductor-chip-mounting circuits) and in which the liquid crystal displays must be discarded is avoided as far as possible.